In general, virtualization is a technique for hosting different guest operating systems concurrently on the same computing platform. With the emergence of hardware support for full virtualization in an increased number of hardware processor architectures, new software virtualization architectures have emerged. One such virtualization technique involves adding a software abstraction layer, sometimes referred to as a virtualization layer, between the physical hardware and a virtual machine (referred to as “VM”).
A VM is a software abstraction that operates like a physical (real) computing device having a particular operating system. A VM typically features pass-through physical and/or emulated virtual system hardware, and guest system software. The virtual system hardware is implemented as software components in the host (e.g., virtual central processing unit “vCPU” or virtual disk) that are configured to operate in a similar manner as corresponding physical components (e.g., physical CPU or hard disk). The guest system software, when executed, controls operations inside the VM, such as the execution and allocation of virtual resources, so that the VM operates in a manner consistent to operations of the physical computing device. As a result, the software virtualization architecture allows for a computing device, which may be running one type of “host” operating system (OS), to support a VM that operates like another computing device that is running another OS type.
Over the last few years, while efforts have been made to improve functionality of VMs, the overall logical architecture of the virtualization layer has experienced little change. The virtualization layer includes a hypervisor, the most privileged component of the virtualization software stack, which runs on top of the hardware resources. The virtualization layer functions similar to an OS kernel—abstracting the underlying hardware resources and isolating software components running on the hypervisor.
While able to access low-level context data (e.g., register values, etc.) from the guest operating system (guest OS) residing in the VM, the virtualization layer is unable to discern higher level context concerning the guest processes, such as the particular type and/or version of the application associated with the active guest process running in the VM. Stated differently, from the context data, the virtualization layer is unable to discern whether the active process pertains to a particular type/version of web browser application (e.g., FireFox® browser, version 24.7) or a particular type/version of a Portable Document Format (PDF) reader (e.g., Adobe® Reader, version 10) for example. Additionally, although the virtualization layer has access to stored data within the entire virtual memory, without additional metadata, it is unable to discern whether that stored data is associated with a process stack or a critical OS data structure.
As a result, the virtualization layer relies on additional data delivery schemes to obtain metadata associated with guest processes running in the VM. One data delivery scheme instruments an event monitoring process as part of or operating in conjunction with the guest OS. This software component, sometimes referred to as a “guest agent,” is configured to provide the virtualization layer with metadata that may assist in the handling of exploit detection. For instance, depending on the OS-type, a particular guest agent may be instrumented into or operating in conjunction with the guest OS and, in response to at least one selected event, provides metadata to the virtualization layer.
Despite having an immense value in exploit detection, the guest agent remains generally unsecure as there are no mechanisms within the software virtualization architecture to protect the integrity, confidentiality and availability of the guest agent. When operating inside the guest OS, the guest agent is at the same privilege level as potential malware being processed within the VM. Hence, the guest agent is highly susceptible to a malicious attack. The loss of proper guest agent functionality may result in a loss of semantic information for the virtualization layer, which may degrade its exploit detection and guest process protection abilities.